Overhead carrier



1956 A. H. HUNTINGTON 2,731,158

OVERHEAD CARRIER Filed July 1, 1954 3 Sheets-Sheet 1 FIG. 2

IN VEN TOR. 9L FRED H. HUNT/N6 MN Jan. 17, 1956 A. H. HUNTINGTON OVERHEAD CARRIER Filed July 1, 1954 3 Sheets-Sheet 2 INVENTOR.

United States Patent C) OVERHEAD CARRIER Alfred Hugh Huntington, Willoughby, Ohio, assignor to The Cleveland Crane & Engineering Company, Wickliife, Ohio, a corporation of @hio Application July 1, 1954, Serial No. 440,657

2 Claims. (Cl. 212-131) The present invention relates to load supporting and moving devices and more particularly to a load supporting and moving device including means for quickly raising and lowering the load.

The principal object of the present invention is the provision of a new and improved load supporting and moving device wherein the load is suspended from an overhead structure by means of cable and including means for taking in and letting out the cables to raise and lower the load, the device being so constructed and arranged that the load may be raised, transported to another location, and lowered within a relatively short period of time without appreciable swinging of the load.

Another object of the present invention is the provision of an overhead load suspending and moving device particularly adapted for use in manufacturing or treating processes where it is necessary to move the object being processed from a first station to a second station in a matter of seconds, the load suspending and moving device being so constructed and arranged that it can quickly raise and lower or lower and rapidly move it to a second station.

Another object of the present invention is the provision of new and improved load supporting and moving device including a load supporting member suspended from an overhead structure by cables so arranged to prevent swinging of the member and including air oper ated means for simultaneously and equally taking in and letting out the cables to raise and lower the load supporting structure comprising a double acting air cylinder, the air operated means being so constructed and arranged that the movement of the load supporting memher is substantially greater than the movement of the piston of the double acting air cylinder.

Another object of the present invention is the provision of a new and improved overhead carrier having power means for moving the carrier, and including load supporting means suspended from the carrier by cables, and means to simultaneously and rapidly take in and let out the cables to raise and lower the load, the control means for the power means for moving the carrier and the means for raising and lowering the load being so constructed and arranged that the load may be selectively automatically raised at a high speed, rapidly transferred to another location, and lowered at a high rate of speed, or selectively raised and lowered at a slow rate of speed.

The invention resides in certain constructions and combinations and arrangements of parts, and further objects and advantages will be apparent to those skilled in the art to which it relates from the following description of the preferred embodiment described with reference to the accompanying drawings forming a part of this specification, in which:

Fig. 1 is a plan view of the overhead carrier embodying the present invention;

Fig. 2 is a front elevational view of the carrier and load supporting means of Fig. 1 with the load supporting means in raised position;

Fig. 3 is an end elevational view of the carrier of Fig. 1 showing the carrier in two positions along its supporting rail, the load being raised in one position and lowered in the other;

Fig. 4 is a view taken approximately along line 4-4 of Fig. 2;

Fig. 5 is a diagrammatic circuit diagram of a control circuit for the apparatus illustrated; and

Fig. 6 is a diagrammatic showing of the hydraulic means for raising and lowering the load.

Referring to the drawings, the reference character A designates generally a carrier for an overhead carrier system supported on and adapted to travel along a runway comprising rails 10 and 11 supported by a superstructure, such as, the frame of a building within which the carrier system is housed, in a manner well known in the art. The carrier A comprises a supporting structure or frame 12 generally rectangular in shape and provided at opposite ends with track-engaging wheels 13 by means of which the supporting structure or frame 12 is supported on and travels along the rails 10 and 11.

A load bar 14 is suspended from the supporting structure or frame 12 by three pairs of tackles or cables 15, 16; 17, 18; and 19, 20. The tackles or cables of each pair are angularly positioned with respect to each other and the pairs of tackles or cables lie in intersecting substantially vertical planes, as will be hereinafter'more readily apparent, and not only serve as the suspending means but as guywires for preventing lateral movement or swinging of the load bar 14, as well as rotation there of about a vertical axis. The right-hand end of the load bar 14 is supported by the pair of tackles or cables 15, 16 connected to the load bar adjacent to its longitudinal centerline. The vertically extending portions of the tackles or cables 15, 16 lie substantially in a vertical plane at right angles to the length of the load bar. The other end of the load bar 14 mounts spaced, parallel across bars 22 connected at their adjacent outer ends by members 23, 24 which define an acute angle when extended, that is bisected by the center line of load bar 14. The other two pairs of tackles or cables 17, 18 and 19, 20 are connected to the members 23, 24 respectively. The tackles or the vertical parts of the pairs of cables 17, 18 and 19, 20 lie in planes which intersect each other substantially upon a vertical plane passing through the longitudinal center line of the platform.

Each tackle is connected to the load bar 14 or the members 23, 24 by means of an adjustable bracket 26 which permits adjustment of the length of the cable. The adjustable brackets for each pair of cables or tackles are pivotally secured to the load bar 14 or members 23, 24 to permit the angle between the brackets to vary as the load bar 14 is raised and lowered.

The load bar 14 is raised and lowered by means of an air-operated cylinder 23 supported along the longitudinal center line of the rectangular frame 12 of the supporting structure. The ram or piston of the cylinder is operatively connected to a crosshead 30 supported transversely of the central portion of the frame 12 for longitudinal movement with respect thereto. The support means for the crosshead 30 comprises spaced parallel guide rods 31, 32 located on opposite sides of the longitudinal center line of the frame 12 and supported parallel thereto. The cross head 30 is connected to the guide rods 31, 32 by bushings 33 located adjacent the four corners of the crosshead. The movement of the crosshead 30 takes in or lets out the tackles supporting load bar 14.

The tackles are each connected to the frame 12 and to the crosshead 30. The frame 12 is provided with a 3 transverse anchor bar 35 adjacent its left-hand end, as the" ffiifi'l' is viewed in Fig. I, f Which the tackles are anchored in the following order, proceeding from the front to the rear of. the frame: tackle 16, tackle 18 tackle' 17, tackle 19", tackle 20 and tackle 1'5. The tackle 16 extends from the anchor bar parallel to the longitudi'nal center line of" the: frame 12 and passes around a sheave rotat'ably supported on the left-hand side of crosshead 30 from whence it doubles back upon itself and, to reverse its direction, it then passes around a sheave 37 rotatably' supported in a horizontal plane by the frame 12. The tackle 16 extends horizontally from the sheave 37 toward the right-hand end of the frame 12 and passes around a sheave 33 and a' sheave 39 located adjacent the right-hand end of frame 12. The sheave 38 is supported horizontally and the sheave 39 vertically. From the sheave. 39 the tackle 16 extends downwardly to the load bar 14'. The tackle is supported in the same manner as the tackle 16,. But uponthe opposite side of. the frame '12,. and, therefore, the supportwill not be described in detail. The sheaves,.however,. for supporting and changing the. direction of the tackle 15} which correspond to thevarious sheaves forsupporting. the tackle 16, have been given thesame reference numerals with a prime afiixed thereto.

The tackle 18 is anchored to the anchor bar 35, extends therefrom parallel to the longitudinal center line of the frame 12,. and passes around a sheave 46 supported on the left-hand end of. the crosshead adjacent the sheave 36. From the sheave 40 the tackle 18' doubles back upon itselfand passes around a sheave 4 1 rotatably supported in a horizontal plane by the frame 12 and a sheave 42 rotatably supported in avertical plane by the frame 12 forwardly of sheave 41 From the sheave 42 the tackle 18 extends downwardly to the load bar 14.

The tackle 17 is anchored to the anchor bar 35 adjacent the tackle 18 and extends from the bar 35 around a sheave 44 onthe crosshead 30 and around ahorizon tally supported sheave 45 and a' vertically supported sheave 46 similar to the sheaves 41, 42, but located closer to the longitudinal center line and the left-hand end of the frame 12. From the sheave 46 the tackle 17 extends downwardly tothe-loadbar 14. g

The pair of tackles 19 and 20 is connected to the frame 12 and the crosshead 30 in the same manner as the pair of tackles 17, 18, but on the opposite side of thelongitudinal center line of frame 12; The description, therefore, will not be repeated but corresponding sheaves are: designated by thesame reference character with a prime mar-k aflixed thereto.

It can now be seenthat movement of crosshead 30 by the air cylinder 28' along the longitudinal center line of frame-12will cause the-tackles to be taken in or let out, depending upon whether the crosshead 30 is moved to the right or to-theleft asitis viewed in Fig. l. The load bar may be moved upwardly and downwardly very rapidly since the vertically depending portion of each tackle is lengthened orshortened by an amount which is equal to twicethe distance travelled by the crosshead 30.

Air for operating:the air cylinder 28 is supplied thereto from reservoirs ortanks 47, 48 mounted on theframe 12 adjacent-the center sectionof its front and rear sides, respectively. The pressure within the air reservoirs 47, 48 is maintained by an air compressor 50 and a motor 51 for driving theair compressor, both being mounted adjacent the right-hand endof frame 1.2. The compressor 50 is connectedto the reservoirs 47, 48 by a line 52 connected to lines 53,- 54' tothe reservoirs 47, 48, respectively.

The-outletof the reservoirs 47; is connected to one inlet of a m-coupling 55 through suitable pressure regulators, lubricato'rs; and a-pre's'sure' gauge; The air from the coupling 55 is supplied to the left-hand side or the right-hand sideas the air cylinder '23 thr'ough a-'-plu'rality o'f solenoid-valves 5'6} 57} 58,69, 60; 619 The-valves 56, 57, 58 control the supply of air to a slow-speed line 63 and a high-speed line 64 connected to the right-hand end of air cylinder 28. When air is supplied to both the lines 63, 64, the piston of air cylinder 28 moves at a high rate of speed toward the left, but when air is supplied only to slow-speed line 63, the piston of air cylinder 28 moves to the left at a slow rate of speed. Similarly, the valves 59, 60, 61 control the supply of air to a slow-speed line 67 and a high-speed line 68 connected to the left-hand end of air cylinder 28. When air is supplied to the slow-speed line 67, the piston of air cylinder 28 moves toward the right at a slow rate of speed and when the air is supplied to both lines 67, 63, the piston moves at a much higher rate of speed. The solenoid valves 56, 57, 58; 59, 66, 61' also function to connect one side of the piston of air cylinder 28 to exhaust through one of the air supply lines when air is being supplied to the other side of the piston in a manner which will be described in detail hereinafter. The high speed and slow speed air supply lines to the cylinder 28 contain adjustable orifices or other metering devices 69 to permit the speed of the piston to be adjusted.

The solenoid valves in the illustrated embodiment may be three-way valves although all ports are not always utilized. One of the ports of solenoid valve 60 is connected to the coupling 55 by a line 70, while one of the ports of solenoid valve 56 is also connected to the coupling55 by a line 71. When the load bar is to be moved downwardly at a slow rate, solenoid valves 56 and 59 are energized. The solenoid valve 59 controls the exhaust connection of the left-hand side of the piston and has one port connected to one port of the solenoid valve 60 by a line 72, and the de-energized position of the valve is such that how of air from the line 72 is blocked. When the valve 59 is energized, the valve is moved to a position connecting the line 72 to atmosphere. The valve60 has its remaining port connected to the slowspeed line 67 and to one port of the valve 61 by a pipe line 73. When the solenoid valve 60 is de-energized, the valve is in a position connecting the slow-speed line 67 to the exhaust line 72, the normal de-energized position of valve 61 blocking the connection between the highspeed line 68 and the valve 60. It may now be seen that the energization of the solenoid valve 59 connects the left-hand end of air cylinder 28 to atmosphere, permitting movement of the piston of the cylinder to the left.

The piston of cylinder 28 is moved to the left slowly by air supplied through line 63 to the right-hand end of the cylinder. The solenoid yalve' 56 has one port connected-to the solenoid valve 57 by a pipe line 74, which in turn has one port connected to the'line 63. When de-energized the solenoidyalve 57 is in a position permitting flow from the line 63 through the valve 57 to the valve 56, while the valve 56 when de-energized is in a position blocking flow from the line '71-through the valve 56 to the line 57. It may now be seen that energization of the solenoid valve 56 moves the valve so that the line 71 is connected through the valve 57 to the line 63 to cause the piston of air cylinder 28 to move toward the left and lower the load bar 14.

To lower the load rapidly solenoid valves 52, 61 are energized in additionto the valves 56, 59 The valve 53 has one port' connected to the connection between the slow-speed line'63 and the'valve 57, and has a second port connected to the high-speed line 64. When the valve 555 is'de-energized his in a position blocking air flow between the solenoid valve STand the high-speed line 64'. Upon energization" of the solenoid valve 58; it is moved to a position permitting air now from the valve'57 through the valve 58to high-speed line 64.

Theenergization'of solenoid valve 61 moves the valve so that the high speed line 68, nowfunctioning as an exha ust" line, is connected to exhaust through the solenoid valve 60, now in its tie-energized position, line '72 and solenoid valve'59 no'vveriergizedz Inthe'event that power fails, the load is immediately stopped since the solenoid valve 59 will be de-energized, moving the valve to close off the exhaust connection. The closing of the exhaust connection to the left-hand side of the piston of the air cylinder will trap air in the cylinder, stopping and holding the load in the position it is when power is lost.

T move the load upwardly at a slow rate of speed air is supplied to the slow speed line 67 by energizing valve 60 to connect line 7t) to line 73 and close line 72. To simplify circuit arrangement the valve 59 may also be energized since the valve 60 will block the connection between line 73 and exhaust line 72. The right-hand side of air cylinder 28 is connected to exhaust by energizing valve 57. The energization of valve 57 moves it so that the slow speed line 63, now functioning as an exhaust line, is connected to atmosphere and so that the connection between the valve 56 and the slow speed line 63 through valve 57 is blocked. To simplify circuit arrangement the valve 56 may also be energized since the solenoid valve 57 will block the air pressure being supplied by line 71.

To raise the load rapidly, solenoid valves 58, 61 are energized in addition to the solenoid valves 56, 57, 59, 60. The energization of solenoid valve 61 connects the highspeed line 68 to the supply line 70, through the valve 60, and the energization of valve 58 connects the high-speed line 64, now functioning as an exhaust line, to exhaust through the valve 57.

The above-described arrangement provides a means for rapidly raising and lowering the load supported by the load bar 14. It will be understood by those skilled in the art that the particular arrangement of solenoid valves may be modified so long as the desired control of the load bar is retained.

The carrier A is moved along the rails 10 and 11 of the overhead system by means of a tractor 75 supported on rail 11 at the right-hand side of the frame 12 as it is viewed in Fig. 3. The tractor 75 includes a reversible electric motor '76 operable to drive supporting wheels 77 for the tractor '75 through a gear drive within a housing 78; The tractor will not be described in detail inasmuch as its construction and operation are conventional and Well understood by those skilled in the art.

The translatory movements of the carrier A, as well as the raising and lowering of the load bar 14, may be controlled, in the illustrated embodiment, from either of two stations. These stations may be a salt bath station and a quench bath station commonly utilized in the treatment of metals since it is often necessary to move the metal from a salt bath to a quench bath within a very short period of time, in some cases the period oftime being as little as 15 seconds. The present carrier is espe cially suitable for use in such a situation.

The control circuit for the carrier A and tractor 75 is so arranged that the load, which may be suspended from load bar 14 by means of hooks 80, is capable of being moved automatically from left to right as viewed in Fig. 3 from a first station which may be a salt bath to a second station which may be a quench bath. When it is desired to start the automatic operation of the carrier, a selector switch 81 indicated in the electrical diagram of Fig. and included in a control station at the first station or salt bath is moved to its automatic position. After moving the switch 81 to the automatic position, a start button 83 at the first station, shown in the circuit diagram, is depressed to energize the solenoid valves 56, 57, 58, 59, so, 61 to rapidly raise the load bar 14. When the load bar 1% reaches its upward position, it engages and raises a weight 84 attached to a limit switch 85 for holding the limit switch in one of its positions. The limit switch 85 has two pairs 86, 87 of normally open contacts which are closed when the load bar 14 supports the weight 84. The closing of the normally open contacts 36 of switch 85 starts the forward travel of the tractor 75 to move the carrier A to a position over the quench tank.

When approaching its second station or quench tank position, a limit switch 88 is actuated, which stops the forward travel of the tractor 75. A limit switch 89 is also actuated by the carrier A when approaching its quench tank position to effect lowering the load bar 14 at a rapid rate.

A control station is also provided at the quench tank station for controlling the movement of the carrier from that station. The control station includes push button switches 92, 93 for raising and lowering the load bar 14 at a slow rate of speed, and push button switches 94, 95 for controlling the forward and reverse operation of tractor 75. The push button switches 92, 93, 94, 95 are shown on the circuit diagram of Fig. 5. The circuit in the illustrated system is so arranged that the automatic travel of the carrier can only be initiated from control panel at the firststation, and so that the rapid lowering and raising of the load bar 14 only occurs during the automatic cycle.

The control panel at the first station also includes push button switches 97, 98 for initiating the raising and lowering respectively of the load bar 14 at a slow rate of speed, and push buttons 99, 100 for initiating the forward and reverse movement respectively of the tractor 7 5 when the selector switch 81 is turned to manual.

The electrical circuit for controlling theoperation of the illustrated embodiment of the invention is shown in Fig. 5. Part of the control circuit is located in the ground and part on the carrier A. As is schematically shown in Fig. 5, connection is made between the carrier A and the ground control stations by means of trolley conductor bars 105, 106, 107, 108, 109, 110, 111, and 112, which engage trolleys 113, 114, 115, 116, 117, 118, 119, and respectively.

In addition to the conductor bars and trolleys for completing the various control circuits, trolley conductor bars 121, 122, and 123 are provided for supplying threephase power to the tractor of the carrier and for supplying power to a transformer 125 mounted on the carrier and having its primary connected to trolleys 126, 127 engaging the conductor bars 121, 122 respectively. The secondary of transformer 125 is provided with terminals 12%, 12? for supplying power to operate the solenoid valves 515-61. The side of the secondary of transformer .125 connected to terminal 128 shall be designated hereinafter as L1 and the side connected to terminal 129 shall be designated as L2. The application of the power to the solenoid valves is controlled by relays energized from the control stations 82, 91.

To start the automatic cycle to rapidly raise the load bar 14, move the carrier from a first station such as a salt bath to a second station such as a quench bath, and rapidly lower the load bar 14, the selector switch 81 is moved to its automatic position and the start push button switch 83 is depressed. This completes a circuit from a secondary terminal 131) of a stationary transformer 131 having secondary terminals 130, 132, through wire 133, now closed contacts 134 of selector switch 81, wire 135, now closed contacts of start push button switch 83, wire 136, coil 137 of a time delay relay 138, and wire 13% to terminal 132 of transformer 131. Energization of the time delay relay 138 closes its normally open contacts 140, 141. The closing of the contacts 140 completes a holding circuit around push button switch 83.

The closing of contacts .141 of relay 13S completes a circuit from L1 by means of trolley 114 connected to L1, trolley conductor bar 106, wire 142, wire 133, contacts 134 of selector switch 81, wire-135, now closed contacts 141, and wire 143 to apply potential to the conductor bar 109 engaged by trolley 117. The trolley 117 is connected by a Wire 144 to the coil of a relay 14-5 having normally open contacts 146, 147, 148, 149, and 156. The other side of the coil of relay 145 is connected to L2 by a wire 151.

The closing of the contacts of relay 145 completes circuits from L1 to energize the solenoid valves 56-61.

The circuit for energizing solenoid valves 56, 59 from L1 includes wire 152 connected to L1, now closed contacts 151) of relay 145, wire 153, solenoid valve 59, and wire 154 to L2. The solenoid valve 56 is connected in parallel with the solenoid valve 59 by a wire 155 connected to wire 153 and a wire 156 connected to L2.

The circuit for energizing solenoid valves 58, 61 from L1, includes Wire 1522, now closed contacts 149 of relay 145, wire 161, solenoid valve 58, wire 162 to wire 163, normally closed contacts 164 or a relay 165 and a wire 166 to L2. The solenoid valve 61 is connected in parallel with the solenoid valve 58 by a wire 167 connected to wire 161 and a wire 168 connected to wire 163.

The circuit for energizing solenoid valves 57, 68 from L1 includes wire 152, wire 169, normally closed contacts 178 of a relay 171, wire 172, now closed contacts 148 of relay 145, wire 1 3, solenoid valve 61), wire 1'74, wire 163, normally closed contacts 164 of relay 165, and wire 166 to L2. The solenoid valve 57 is electrically connected in parallel with the solenoid valve 66 by a wire 175 connected to wire 173, and a wire 176 connected to wire 163.

When the load bar 14 reaches the upper limit of its travel, it supports the weight 84 of switch 85, permitting the contacts of the switch, normally held open by the weight, to be closed. The closing of its contacts 86 starts the forward travel of the tractor by completing a circuit to a relay 177 for energizing the contactor for operating the tractor in a forward direction. This circuit is completed from trolley 117, which has been connected to L2 in the manner described above, through wire 144, wire 178, contacts 147 of relay 145, wire 179, now closed contacts 86 of weight limit switch 85, wire 181, normally closed contacts 182 of down relay 171, wire 183, wire 184, normally closed contacts 185 of forward travel stop limit switch 88, wire 186, normally closed contacts 187 of a reverse relay 188 controlling the energization of the contactor for operating the tractor in a reverse direction, wire 189, relay coil 198 of forward relay 177, and wire 191 to L2. The forward travel of the tractor to the second station is stopped by the actuation of limit switch 88, which breaks the circuit to relay 177.

As the tractor approaches the second station, the limit switch 89 is closed, completing a circuit to down relay 171, which when energized causes the load bar 14 to move downwardly at a rapid rate. The circuit for energizing relay 171 from L1 includes wire 142 connected to L1, automatic contacts 134 of selector switch 81, wire 135, trolley bar 195, trolley 113, wire 193, now closed contacts 194 of limit switch 89, wire 195, solenoid coil 196 of relay 171, and wire 197 connected to L2.

The energization of down relay 171 opens its contacts 179 breaking the circuit to the solenoid valves 57, 68, which was completed through the contacts 148 of the relay 145. The de-cnergization of the valves 57 and 68 causes the load bar 14 to be lowered rapidly in the manner hcreinbefore described.

Upon the completion of the automatic cycle at the second station, further movements of the carrier A are controlled by moving the selector switch 81 to its manual position. The moving of the selector switch to the manual position connects one side of the push button switches 98, 93, 97, 92 for controlling the movements of the load bar 14 to L1. The circuit from L1 includes trolley 114, trolley bar 196, wire 142, wire 281), contacts 293 of selector switch 81, and wire 284 connected to the switches 92, 93, 97,

One side of the switches 94, 95, 99, 188 for controlling the forward and reverse movement of the tractor is also connected to L1 by tl e closing of the contacts 283 when the selector switch is moved to manual. This circuit in cludes trolley 114, trolley bar 186, wire 142, wire 28%, now closed contacts 293, and wire 285 connected to the one side of the switches 94, 95, 99, and 188.

When it is desired to move the load bar upwardly at a slow rate, either push button switch 92 or push button switch 97, the two being connected in parallel, may be depressed to connect L1 to the trolley conductor bar 108 and energize a relay 207 on the carrier A having normally open contacts 298, 209. The circuit for energizing the relay 287 from the trolley conductor bar 1198 includes trolley 116, wire 210, relay coil of relay 207, and wire 212 connected to L2. The closing of contacts 288, 259 of the relay 207 completes circuits to energize the solenoid valves 56, 59 and the solenoid valves 57, 60 by connecting the valves to L1 through wire 152. The circuit from L1 to solenoid valves 57, 60 includes wire 152, wire 169, normally closed contacts 178 of relay 171, wire 172, now closed contacts 269 of relay 207, and wire 211 to wires 173, and 17 5 connected to valves 69, 52 respectively.

When the load bar 14 reaches the upper limit of its travel, it lifts the weight 84 of switch 85 as mentioned hereinbefore, closing its normally open contacts 87 to complete a holding circuit to the coil of relay 207, keeping the solenoid valves 56, 59 energized when the load is lifted to maintain a positive pressure in the air cylinder 28, thereby ensuring that the load will not be dropped. This holding circuit includes wire 152 connected to L2, now closed contacts 87 of weight limit switch 85, wire 213, connected to wire 210 to the coil of relay 287.

When the load bar 14 is to be lowered at a slow rate, either the push button switch 98 or the push button switch 93 may be depressed to connect the trolley conductor bar 107 to L1 through the closed contacts 283 of the selector switch 81 and the wire 204. The push button switches 93, 98 are connected in parallel. The potential applied to the trolley conductor bar 107 is transferred to the carrier by trolley 105, which is connected to relay coil 215 of relay by a wire 216. The relay coil 215 is connected to L2 by wire 217. The energization of relay 165 closes its normally open contacts 218 and opens its normally closed contacts 164. The closing of its normally open contacts 218 completes a circuit from L1, through wire 152 to the solenoid valves 56, 59. The opening of the normally closed contacts 168 breaks the circuits for energizing solenoid valves 57, 58, 60, 61 regardless of what other relays may be energized by ensuring that only the solenoid valves 56, 59 are energized causing the load bar 14 to move downwardly at a rapid rate.

The forward and reverse movement of the tractor 75 of the carrier A may becontrolled from either the control station at the salt tank or the control station at the quench tank. The tractor may be caused to move forward from the salt tank by depressing push button switch 99, which has one side connected to L-1 by wire 220, now closed contacts 203 of selector switch 81, wire 200 connected to trolley bar 106, and trolley 114 connected to L-1. The other side of the push button switch 99 is connected to trolley bar 110', and depressing the switch 99 applies L1 to the bar. The trolley bar 110 is engaged by trolley collector 118,- which is connected to the relay coil 190 of the forward relay for operating the forward contactor for the tractor motor by wire 184, normally closed contacts of limit switch 88, wire 186, normally closed contacts 187 of reverse relay 188, and wire 189 to'the coil of forward relay 177. The relay coil 190 of forward relay 177 is in turn-connected to L2 by wire 191.

The tractor may also be caused to moved in a forward direction by depressing push button 94- located at the quench tank control station. The push button switch 94 is connected in parallel with the push button switch 99 and the limit switch 185' by wire 221 connected to wire 220 and a circuit including wire 222 connected to one side of the switch 94, trolley bar 111, trolley collector 119, and wire223 connected to wire 186. The circuit for operating the forward relay from the wire 186 is the same as that described above in connection with the push button switch 99;

The tractor may be caused to move in a reverse direction by depressing either push buttonswitch 95 located at the quench tank stationor push button switch 100 lo 9 cated at the salt tank control station. Switches 95, 100 are connected in parallel, each having one side connected to wire 220, which is connected to L4, as described above, and their other sides connected to trolley bar 112. When one or" the push button switches 95, 100 is depressed, L-1 is applied to the trolley bar 112, causing energization of the reverse relay by a circuit from trolley bar 112 which includes trolley conductor 120, wire 225, normally closed contacts 226 of forward relay 177, wire 227, relay coil 228 of reverse relay 188, and wire 229 connected to L2. Energization of the relay coil 228 causes the closing of contacts in the circuit to the reverse contactor for controlling the operation of the tractor 75.

An apparatus constructed according to the present invention is capable of hoisting a load approximately seven feet, traveling a distance of approximately 10 feet and lowering the load in a period of time less than 12 secends.

it may now be seen that the present invention provides an apparatus capable of swiftly raising a load, transporting it to a second location, and lowering the load at the second location. Means have been provided to accomplish the above cycle automatically, while permitting the movement of the carrier as well as the raising of the load to be done non-automatically, if so desired. The means for raising and lowering the load is so constructed that the load is moved a much greater distance than the member for actuating the movement of the load, thereby eflecting rapid raising and lowering for short travels of the actuating member.

The preferred embodiment of the invention has been described in considerable detail, and it will be apparent that the invention is not limited to the constructions shown, or to the uses referred to, and it is my intention to cover hereby all adaptations, modifications, and changes which come within the practice of those skilled in the art to which the invention relates and the scope of the appended claims.

Having thus described my invention, I claim:

1. In apparatus of the character referred to, an overhead trackway, a supporting member movably supported on said trackway, a supported member, power means for moving said supporting member along said trackway, means comprising three pairs of cables for suspending said supported member from said supporting member, means for operatively connecting the respective cables of each pair to one of said members at spaced points, means for operatively connecting said cables to the other of said members so that the respective cables of each pair are connected to said other of said members at substantially the same point but spaced from the points at which the other pairs of cables are connected, air operated means for simultaneously letting out and simultaneously taking up the respective cables of each pair including control means for controlling the operation of the air operated means comprising first switch means for stopping the operation of said air operated means and starting the operation of said power means to move said supporting member along said trackway, means for operating said switch means to start said power means when said supported member is within a predetermined distance of said supporting member, and second switch means to stop the operation of said power means and start the operation of said air operated means to let out said cables to lower said supported member.

2. In an apparatus of the character referred to, an overhead trackway; a supporting structure movably supported on said trackway, power means for moving said supporting structure along said trackway, a supported structure; means comprising three pairs of cables for suspending said supported structure from said supporting structure; means for operatively connecting the respective cables of each pair to one of said structures at spaced points; means for operatively connecting the said cables to the other of said structures so that the respective cables of each pair are connected to the other of said structures at substantially the same point, but spaced from the points to which the other pairs of tackles are connected; a sheave for each of said cables supported on said one structure and engaged by its corresponding cable; and means on said one of said structures to simultaneously take in and let out the cables of each pair, the last said means comprising a movable member operatively connected to said cables intermediate said sheaves and the point of connection of said cables to said one structure, air operated means for moving said member, and control means for said air operated means and said power means including first switch means for starting the operation of said power means when said supported structure approaches its raised position and second switch means to stop the operation of said power means and start the lowering of said supported structure when said supported structure approaches a station where the supported structure is to be lowered.

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